Alhazen's problem

Etymology
Named for a tenth-century Arab mathematician Ibn al-Haytham, whose latinized name, Alhacen, may be rendered as Alhazen.

Proper noun

 * 1)  A mathematical problem in which lines drawn from two points in the plane of a circle must meet at a point on the circumference, making equal angles with the normal at that point.

Translations

 * Portuguese: problema de Alhazen